Adjustment Procedures; Cassette Deck - Grundig PA 2 Service Manual

Abgleichvorschriften / Adjustment Procedures

Adjustment Procedures

GB

Cassette Deck

Test Equipment:
Frequency counter, AF voltmeter, AF generator, distortion analyzer, wow and flutter meter, Cr test cassette 448 A, torque test cassette 456.
Adjustment
1. Tape speed Frequency counter to Pin 1 resp. 5 of P106.
Insert test cassette 448 A.
Play back 3150Hz.
2. Take-up torque on Load the torque test cassette 456.
Start Function: Start.
3. Wow and flutter Wow and flutter meter to Pin 1 resp. 5 of P106.
Load test cassette 448 A.
Play back 3150Hz.
4. Head gap angle Connect AF voltmeter to Pin 5 of P106 (left channel) or to
(Azimuth) Pin 1 of P106 (right channel).
Load test cassette 448 A, play back 10kHz.
E
5. Playback level AF voltmeter to test point
Reference tape (right channel).
scanning Insert test cassette 448 A .
(Dolby level) Play back 315Hz (250 nWb/m).
Dolby off.
6. Erase frequency Frequency counter to test point
Insert a recordable cassette, Cr tape (IEC II).
Function: Record-Start.
7. Erase current AF voltmeter to test point
Insert a recordable cassette with Cr tape (IEC II).
Function: Record-Start.
8. Record blocking Connect the AF voltmeter to test point
circuits or to test point
(bias filter) board.
Insert a recordable cassette with Cr tape (IEC II).
Function: Record-Start.
9. MPX-filter Connect the AF generator (f
(19kHz stereo pilot 400mV) to the Pin 2 and 4 of P106.
tone)
Connect the AF voltmeter to the
test points
or D2 (right channel).
Function: Record-Start, ALC OFF, Dolby off.
10. Frequency AF voltmeter to test point
response on D2 (right channel).
Playback Insert test cassette 448 A.
Play back the 250Hz / 12.5 kHz frequency recording on the
tape.
Dolby off
2 - 5
Preparations
Tape run Tape run
"Normal" "Reverse"
D1 (left channel) or
L1 (R263).
L1 (in parallel with R263).
TP3 (left channel)
TP4 (right channel) on the audio circuit
= 315Hz, f
1 2
D1 (left channel)
D1 (left channel) or test point
With adjustment control R482 (Logic board) set the
frequency to 3150 Hz
On START, the torque should be 30 to 60 x 10
≈ 40 g-cm.
Deviation < 0.2% (IEC unwtd).
Playback measuring time ≥ 30 seconds.
Tape direction: "Normal"
With the head adjustment screw E set the left or right
channel to maximum level.
Then connect the left channel in parallel with the right
channel (Pin 1 and 5 of P106). By minimum re-adjustment
of the head adjustment screw E set the output level to
maximum.
Turn around the test cassette.
Tape direction: "Reverse"
F
Adjustment with head adjustment screw F is the same as
in the "Normal" tape direction.
D2 Set the playback level with the adjustment controls R135
(left) or R136 (right) to 308mV
When using a test cassette with 200 nWb/m set the
playback level to 245mV
The oscillator frequency should be 85kHz
Adjust with L111.
Erase current: 150 mA ± 10% measured at R263
= 150mV ± 10%.
Adjust for minimum RF with F111 at test point
channel) and F112 at test point
= 19kHz, ca. Set AF Generator output during Record so that at 315Hz
the voltage measured at the test points
is U = 245mV (= 0dB).
o
≤
At 19kHz = U
o
Adjust with F101 (left channel) or F 102 (right channel).
If the levels between U
D1 and D2 differ by more than + 1.5dB cut the bridges
B1 (C101), B2 (C103) left channel, or the bridges B3
(C102), B4 (C104) right channel.
V f (12.5kHz)
o 2
V f (250Hz)
o 1
Adjustment Procedure
±
0.1% .
-4
±
0.5dB.
±
0.5dB.
±
10kHz.
TP4 (right channel).
D1 and
47.7mV (≤ –30dB).
f (250Hz) and U f (12.5kHz) at
o 1 o 2
= +1 ± 0.5dB
GRUNDIG Service
PA 2 / PA 3
Nm
TP3 (left
D2